Abstract: The straw fibers were treated with different methods and modifiers, and blended with poly(butylene succinate)(PBS) to modify PBS. The straw fiber/PBS composites were prepared by hot-pressing. The effects of boiling processes and microwave treatment on the extraction of the straw fibers, as well as impacts of the type of modifiers and its addition on the straw fiber and properties of the straw fiber/PBS composites were studied. SEM was used to observe the surface morphology of the straw fibers before and after the treatment. The results show that straw fibers boiled for 30min twice, processed continuously by microwave for 15min, respectively get the best specimen. The straw fibers treated in the latter way have a looser property but larger specific surface than that processed the former, and the straw fiber/PBS composites have a better combination property and the best mechanical property under stearic acid condition of about 3.5%.